Polymerization of olefinic hydrocarbons



March 2, 1948. c. B. LINN I POLYMERIZATION OF OLEFINIC HYDROCARBONS IFiled May 31, 1945 e w, m z x 7 m Z 35 Z F i Z 7 6 J 4 3 2 7f #arzzeyPatent ed Ma .z,-1948 POLYMERIZATION F OLEFINIC HY DROCARBON S Carl B.Linn, Riverside, IIL, assignor to Universal Oil Products Company,Chicago, Ill., a corporation of Delaware Application May 31, 1945,Serial No. 596,922

This invention relates to the polymerization of oleflnic hydrocarbons inthe presence of a special type of catalyst which I have heretoforedisclosed for use in the alkylation of isoparaflins with olefins in mycopending application Serial No. 424,783, now U. 8. Patent No.2,430,181, flled December 29, 1941. vention relates to thepolymerization of propylene and butylenes into normally liquidhydrocarbons boiling within the approximate range of gasoline.

An object of this invention is to polymerize olefinic hydrocarbons inthe presence of a liquid catalytic material.

Another object of this invention is to convert propylene and butylenesinto normally liquid hydrocarbons in the presence of a liquid catalyst.

A further object of this invention is to polymerize oleflnichydrocarbons including monooleflns and polyoleflns in the presence of acata-' lyst mixture comprising hydrogen fluoride as its essential activeingredient.

One specific embodiment of this inventionrelates to a process forproducing hydrocarbons of higher molecular weight which comprisesreacting an oleflnic hydrocarbon having at least 3 carbon atoms permolecule at polymerizing conditions in the presence of liquid hydrogenfluoride 14 Claims. (Cl. 260-683.15)

' and higher olefins, may be obtained also by cata- More particularly,this ,inp and an inorganic salt selected from the group consisting ofthe alkali metal fluorides and sulfates.

Another embodiment of this invention relates to a polymerization processwhich comprises reacting an oleflnic hydrocarbon having at least 3carbon atoms per molecule in the presence of a major proportion byweight of liquid hydrogen fluoride and a minor proportion 01' aninorganic salt soluble in liquid hydrogen fluoride and selected from thegroup consisting of the alkali metal fluorides and sulfates.

A further embodiment of this invention relates to a polymerizationprocess which comprises reacting an oleflnic hydrocarbon having at least3 carbon atoms per molecule in the presence of a liquid hydrogenfluoride catalyst having dissolved therein a minor proportion of analkali metal fluoride.

Normally gaseous and liquid olefinlc hydro carbons which arepolymerizable by the process of the-present invention occur togetherwith parafiinic or saturated hydrocarbons in commercial hydrocarbonmixtures such as those encountered in the cracking of petroleum, in gasmaking processes, and as by-products of various chemical industries.Normally gaseous monooleilns, such as propylene and butylenes. andnorlytic dehydrogenation of parafllns, by pyrolysis of certainparaflinic hydrocarbons, and by dehydration of alcohols. Polyoleflns andcyclic oleflns are also oleflnic hydrocarbons which may be polymerizedin my process and these hydrocarbons include particularly butadiene,isoprene, cyciohexene, alkyl cyclohexenes, and cyclopentenehydrocarbons.

In general, oleflns have a relatively high activity and even under mildcatalytic influence they exhibit this activity by their pronouncedtendency to polymerize and form substances of higher molecular weights.This process is particularly effective for converting propylene andbutylenes into normally liquid polymers.

The present process is directed particularly to the production ofpolymers containing from about 6 to about 12 and more carbon atoms permolecule from propylene and butylenes. The preferred polymer productsboil at temperatures within the approximate boiling range of commercialgasoline. These polymers containing from about 6 to about 12 carbonatoms per molecule are useful for blending with straight-run gasoline toincrease its antiknock value.

By the addition to liquid hydrogen fluoride of an inorganic salt solubletherein, and particularly an alkali metal fluoride or sulfate, theordinarily-vigorous reaction of hydrogen fluoride on catalyticpolymerization reactions of olefins is moderated. Thus, I have foundthat substantial yields of liquid polymers of relatively low molecularweights are produced when propylene, butylones, and higher olefins arereacted at temperatures of from about -50 to about.250 C., but

preferably at a temperature of from about 20 gen fluoride and a minorproportion of an inorganic salt soluble therein. The polymerizationtreatment is generally carried out at a pressure suilicient to maintainthe reacting hydrocarbons and catalyst in substantially liquid phase.

Accordingly, the present invention deals with a hydrogen fluoridepolymerization catalyst modified by the addition thereto of anon-oxidizing salt which moderates the action of hydrogen fluoride andinfluences the polymerization reaction in such a way as to improve theyield and quality of relatively low boiling but normally liquidproducts. In fact, the polymers formed in the presence of my mixedcatalyst comprising. hydrogen fluoride and an alkali metal salt differconsiderably from polymers formed from the same oleflnic charging stockbut in the presence of substantially anhydrous hydrogen fluoride as thesole catalyst. In the presence of my mixed catalyst, mono-olefinichydrocarbons are converted into polymers comprising essentiallymono-olefinic hydrocarbons, whereas in the presence of substantiallyanhydrous hydrogen fluoride, the same mono-oleflnic hydrocarbon chargingstock undergoes conjunct polymerization and forms a. complex mixture ofhydrocarbons containing paraflins, olefins, cyclic hydrocarbons and arelatively high proportion of conjugated dioleflns. The presence ofconjugated dioleilns in the polymer formed in the presenc of hydrogenfluoride as the sole catalyst is evidenced by the so-called specificextinction coeflicient obtained by ultraviolet absorption analysis ofthe hydrocarbon products. In order to interpret the results of theseultra-violet absorption analyses, use is made of the specific extinctioncoefllcient," which is equal to log g CL where Io=intensity of incidentlight (cell filled with isooctane) I=intensity of transmitted light(cell fllied with solution of polymer in iso-octane solvent)C=concentration of polymer in cell in grams per liter L=length of cellpath in centimeters Continuous-operation of my process may be carriedout by passing a mixture of an olefincontaining hydrocarbon fraction anda mixture of hydrogen fluoride and an alkali metal fluoride or sulfatethrough a suitable reactor or group of reactors, separating liquidpolymers from unconverted oleflns and catalyst mixture and recycling theunconverted oleflns and catalyst mixture to the polymerization zone ofthe process.

The following example is given to indicate results obtained by thepresent process, although with no intention of limiting the scope of theinvention in exact correspondence with the numerical results presented.

150 grams of propylene, 77 grams of liquid hydrogen fluoride or 99%concentration, and 20 grams of potassium acid fluoride were contacted at95 C. for two hours in an autoclave equipped with a pressure-sealedstirring device. The reaction product consisted of 80 grams of liquidhydrocarbon polymer and 100 grams of isopropyl fluoride, the latterformed by direct union of "hydrogen fluoride with propylene. After beingrelatively high proportion of conjugated unsaturation. The results shownin a later example indicate a greater simplicity of the polymers formedinthe presence of my hydrogen fluoride-alkali metal salt catalyst thanin polymers formed in the presence of anhydrous hydrogen fluoride.

The alkali metal fluorides and sulfates utilizable in the presentprocess as diluents or spacing agents for a liquid hydrogen fluoridepolymerization catalyst comprise generally the fluo= rides and sulfatesof sodium, potassium, rubidi= um, and cesium, and particularly thefluorides and sulfates of sodium. These fluorides and sulfates aresoluble to a substantial extent in liquid hydrogen fluoride,particularly of 90 to 100% hydrogen fluoride concentration. Ordinarilythe mixed catalyst utilized in my polymerization process comprises fromabout 0.5 to about 30% by weight of the inorganic salt.

My polymerization process may be carried out in a batch operation but itis effected preferably in continuous types of operation. In batch typetreatment an olefinic hydrocarbon, and generally a monoolefinichydrocarbon or a hydrocarbon fraction containing mono-oleflns, may beagitated with a mixture of hydrogen fluoride and an alkali metalfluoride or sulfate in an autoclave or other reactor of suitable design.It is usually necessary to include a cooling zone or other heat exchangemeans in the polymerization zone or between such zones if a multiplepolymerization reactor system is employed.

washed with caustic and with water, the liquid hydrocarbon polymer had arefractive index, 11 of 1.4485. This hydrocarbon oil contained 0.1%fluoride. had a bromine 'number of 49 and an average molecular weight of257. It was subjected to an ultra-violet absorption analysis in whichthe specific extinction coefficients were determined for wave lengthsbetween 220 and 275m These results which are expressed graphically inthe at tached drawing show that the polymer formed in the presence of mycomposite catalyst is less complex and contains a lower percentage ofconjugated double bonds than present in similar polymer produced at thesame reaction temperature in the presence of anhydrous hydrogenfluoride. The operating conditicnsused in these runs with the hydrogenfluoride-potassium acid fluoride catalyst and with hydrogen fluoride andthe results obtained are given in the table.

Table Run No 1 2 Temperature, "C 95 Contact Time, Hours 2 2 Charged,grams:

Propylene 150 150 Hydrogen fluoride 7'. 87 Potassium Acid Fluoride 20 0Recovered, grams:

Liquid Polymers so 143 Isopropyl fluoride 6 Properties of Product:

7m" 1. 4485 1.4587 Wt. Per Cent Fluorine 0. 10 0.12 Bromine Number 49 79Molecular weight 257 240 Cale. Br. Number for found M. W 64 67 Wt. PerCent of 204 C. E. P. Gaso 22 22 Ultra-violet absorption analysisSpecific Extinction Coeihcient Wave length m 220 3. l 7. 2 2.3 6. 9 1. 96. 8 L8 7. 4 l. 9 8. .i 1.9 8. 7 l. 8 9. 0 1. 6 8. 7 1.3 7. 8 0. 9 (i. 4O. 6 4. 9 0. 4 3. 5

The foregoing specification and example indicate the character of theprocess of the present invention and the nature of results obtainablealthough neither section is introduced to unduly limit the generallybroad scope of the invention.

I claim as my invention:

1. A process for producing hydrocarbons of higher molecular weight whichcomprises polymerizing an oleflnic hydrocarbon having at least 3 carbonatoms per molecule in the presence of a'catalyst consisting essentiallyof liquid hydro-.

gen fluoride containing an inorganic salt selected from the groupconsisting of the alkali' metal fluorides and sulfates.

2. A process which comprises polymerizing an oleflnic hydrocarbon havingat least 3- carbon atoms per molecule at a temperature of from about--50 to about 250 C. in the presence of a catalyst consistingessentially-of liquid hydrogen fluoride containing an inorganic saltselected from the group consisting of the alkali metal fluorides andsulfates.

' 3. A polymerization process which comprises polymerizing an oleflnichydrocarbon having at least 3 carbon atoms per molecule in the presenceof a catalyst consisting essentially of liquid hydrogen fluoride havingdissolved therein a minor proportion by weight of an inorganic saltsoluble in liquid hydrogen fluoride and selected from the groupconsisting of the alkali metal fluorides and sulfates.

4. A polymerization process which comprises polymerizing an oleflnichydrocarbon having at least 3 carbon atoms per molecule in the presenceof a catalyst consisting essentially of liquid hydrogen fluoride havingdissolved therein a minor.

proportion by weight of an alkali metal fluoride.

5. A process for producing, hydrocarbons of higher molecular weightwhich comprises polymerizing an oleflnic hydrocarbon having at least 3carbon atoms per molecule at a temperature of from about 50 to about 250C. in the presence of alcatalyst consisting essentially of liquidhydrogen fluoride containing an inorganic salt selected from the groupconsisting of the alkali metal fluorides and sulfates.

6. A polymerization process which comprises polymerizing an oleflnichydrocarbon having at least 3 carbon atoms per molecule at a temperatureof from about --50 to about 250 C. in the presence of a catalystconsisting essentially of liquid hydrogen fluoride having dissolvedtherein A 6 8. A polymerization process which comprises vpolymerizing anoleflnic hydrocarbon having at least 3 carbon atoms per molecule atatemperature of from about 20 to'about 150 C. in the presence of acatalyst consisting essentially of liquid hydrogen fluoride havingdissolved therein a minor proportion by weight of an alkali metal 9. Apolymerization process which comprises polymerizing propylene at atemperature of from about 20 to about 150 C. in the presence of acatalyst consisting essentially of liquid hydrogen fluoride havingdissolved therein a minor proportion by weight of an alkali metalfluoride.

-10. A polymerization process which comprises polymerizing butylene at atemperature of from about 20 to about 150 C. in the presence of acatalyst consisting essentially of liquid hydrogen fluoride havingdissolved therein a minor proportion of an alkali metal fluoride.

11. Apolymerization process which comprises polymerizing propylene andbutylene at a temperature of from about 20 to about 150 C. in thepresence of a catalyst consisting essentially of liquid hydrogenfluoride having dissolved therein a minor proportion of an alkali metalfluoride.

12. -A process for producing hydrocarbons of higher molecular weightwhich comprises polymerizing an oleflnic hydrocarbon in the presence ofa catalyst consisting essentially of a solution predominating in liquidhydrogen fluoride and 1 containing a minor proportion of an inorganicsalt selected from the group consisting of the alkali metal fluoridesand sulfates.

13. A process for producing hydrocarbons of higher molecular weightwhich comprises poly-- merizing an oleflnic hydrocarbon in the presenceof a catalyst consisting essentially of a solution predominating inliquid hydrogen fluoride and containing a minor proportion of an alkalimetal fluoride.

14. A process for producing hydrocarbons of higher molecular weightwhich comprises polymerizing an oleflnic hydrocarbon in the presence ofa catalyst consisting esentially of a solution predominating in liquidhydrogen fluoride and containing a minor proportion of an alkali metalsulfate.

CARL n. REFERENCES orrnn The following references are of record the vflle of this patent: I

UNITED STATES PATENT Name Number mu Linn et a1. Jan. 9, 1945

